1. Field of the Invention
The present invention relates to an information recording method of recording information by irradiating a phase change recording layer material with a laser beam to cause phase changes therein. The present invention also relates to an information recording device, an optical information recording medium, a program for recording information and a storage medium.
2. Discussion of the Background
As optical information recording media in which information is recorded and played back by irradiation of a laser beam, there are optical information media dedicated for playback only, write-once optical information recording media in which information can be written only once and rewritable optical information recording media in which information can be overwritten.
Among the rewritable optical information recording media, CD-RWs, DVD-RWS, DVD+RWs and DVD-RAMs use phase change materials as recording layer materials to utilize phase changes between a crystal state and an amorphous state or a crystal state and a crystal state for recording information. Generally, these phase change optical information recording media use pulse patterns in which the power level of a laser beam is modulated into three levels (i.e., recording level (heating pulse), bias level (cooling pulse) and erasing level).
Detailed conditions for these pulse patterns vary depending on a recording linear velocity and rise-up pulse accuracy of the information recording device used, materials and structure of the optical information recording medium used, etc.
For example, when information is recorded in the same optical information medium using the same information recording device, the amount of energy required to raise the temperature of the recording layer in a high recording linear velocity range is large relative to that required to raise the temperature of the recording layer in a low recording linear velocity range. Therefore, recording is performed under conditions such that the recording power in the high recording linear velocity range is high relative to that in the low recording linear velocity range or the width time of a heating pulse in a multiple pulse portion in a recording pulse pattern which is constituted of a combination of the heating pulse and a cooling pulse, is expanded.
Thus, information on standard pulse patterns for each recording linear velocity is input in the optical information recording media in many cases. However, since there are differences among information recording devices, information is not always recorded in an optical information recording medium with good recording properties.
Optimum pulse patterns for recording vary depending on combinations of the information recording device and optical information recording medium used and the recording linear velocity. Therefore it is necessary to perform recording under conditions suitable for each combination to record information with good recording properties.
Currently, typical information recording devices set up recording conditions customized to combinations of an optical information recording medium and a recording linear velocity in advance and store the customized recording conditions in their memory. When an optical information recording medium is loaded in such an information recording device, in most cases the information recording device recognizes the kind of the optical information recording medium, reads the recording conditions set up therein and records information in the optical information recording medium under the recording conditions.
In addition, published unexamined Japanese Patent Application (hereinafter referred to as JOP) No. 2001-283443 discloses an optical information recording medium having a rewritable area in which individual drive control information is recorded to perform optical recording and playback under optimum conditions based on this drive control information.
Furthermore, JOP No. 2003-109218 discloses another recording method. That is, the recording method obtains no optimum parameter when an apparatus is the same as that used for preceding recording and optimum parameters to the apparatus have already been recorded on an information recording medium in the case that time does not elapse from the preceding recording by a prescribed period, and the recording method records information on the basis of the optimum parameters recorded on the medium. Or this method selects prescribed parameters to obtain optimum parameters and records information on the basis of the obtained optimum parameters. Thus the method can reduce the time required to obtain the optimum parameters.
However, it is impossible to use these methods for a case where an information recording device records information in an optical information recording medium which is marketed after the information recording device is marketed because the recording device does not recognize the recording medium. The same is true for a case where optimum recording conditions for the information recording device are not set in the recording medium. Even when information can be recorded in such a combination, one of the previously recorded conditions is used and therefore the recording is not performed with good recording properties in most cases. Consequently, applicability of these methods to various kinds of optical information recording media is limited.
Suppose that there is an optical information recording device which records information under one of the recording conditions previously recorded therein when an optical information recording medium storing no optimum recording conditions is set in the information recording device. If this information recording device has a maximum recording linear velocity VAh lower than that of the maximum recording linear velocity VMh of the information recording medium, the information recording device records information at the maximum recording linear velocity VAh instead of VMh in the optical information recording medium under one of the conditions previously recorded in the information recording device. That is, information is recorded in the optical information recording medium at the linear velocity VAh under non-optimum recording power and non-optimum pulse pattern conditions. When such poor recording is performed, data which have been recorded in the optical information recording medium may be damaged, or there is a possibility that the optical information recording medium cannot be mounted on the information recording device.
As discussed above, it is disadvantageous to use an optical information recording medium which is not recognized by an information recording device or in which optimum recording method therefor is not recorded, namely such a recording medium is not suitable for a practical use. Thus, since a new optical information recording medium having an improved maximum linear velocity as mentioned above is brought into the market a certain period of time after an information recording device is marketed, the life of the information recording device surely comes to an end at that time. This results in waste of a large number of information recording devices.
To avoid this problem, it is necessary for an information recording device to record information with good recording properties even in an optical information recording medium unrecognized thereby. To achieve this, information on the recording methods stored in an information recording device is necessary to be overwritten to recognize the optical information recording medium as known medium. Currently, information recording device manufacturers provide a web site from which users are guided to access and install version upgrade software of the firmware on their own. This installation is dependent on free will and skills of each user and thus the actual installation ratio is low. Therefore, this is not practical.
In addition, whenever a new optical information recording medium is introduced into the market, the information recording device manufacturers are required to take measures for the new optical information recording medium. This is a heavy burden for not only manufacturers who need to prepare upgraded firmware but also users who are required to install the new upgraded firmware. Thus, this is also not practical in terms of this point.
Because of these reasons, a need still exists for a method of setting up conditions under which an information recording device can record information with good recording properties in an information recording medium which is not recognized by the information recording device. Further, as mentioned above, the optimum recording conditions vary depending on materials, structures and specifications of the information recording medium and structures and specifications of the information recording device. Therefore, to easily obtain settings for recording information with good signal characteristics in an optical information recording medium unrecognized by an information recording device, it is preferred to determine characteristic values of the optical information recording medium, serving as a definite indicator for a setting method of determining optimum recording conditions.